Vascular endothelial growth factor (VEGF) is known to be required for the action of antidepressant therapies but its impact on brain synaptic function is poorly characterized. Using a combination of ...electrophysiological, single-molecule imaging and conditional transgenic approaches, we identified the molecular basis of the VEGF effect on synaptic transmission and plasticity. VEGF increases the postsynaptic responses mediated by the N-methyl-D-aspartate type of glutamate receptors (GluNRs) in hippocampal neurons. This is concurrent with the formation of new synapses and with the synaptic recruitment of GluNR expressing the GluN2B subunit (GluNR-2B). VEGF induces a rapid redistribution of GluNR-2B at synaptic sites by increasing the surface dynamics of these receptors within the membrane. Consistently, silencing the expression of the VEGF receptor 2 (VEGFR2) in neural cells impairs hippocampal-dependent synaptic plasticity and consolidation of emotional memory. These findings demonstrated the direct implication of VEGF signaling in neurons via VEGFR2 in proper synaptic function. They highlight the potential of VEGF as a key regulator of GluNR synaptic function and suggest a role for VEGF in new therapeutic approaches targeting GluNR in depression.
Devic's neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that ...autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial.
To explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgG(AQP4+), NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats.
We showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively). In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model.
We establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO.
Bone is the most common metastatic site for breast cancer. Estrogen-related-receptor alpha (ERRα) has been implicated in cancer cell invasiveness. Here, we established that ERRα promotes spontaneous ...metastatic dissemination of breast cancer cells from primary mammary tumors to the skeleton. We carried out cohort studies, pharmacological inhibition, gain-of-function analyses in vivo and cellular and molecular studies in vitro to identify new biomarkers in breast cancer metastases. Meta-analysis of human primary breast tumors revealed that high ERRα expression levels were associated with bone but not lung metastases. ERRα expression was also detected in circulating tumor cells from metastatic breast cancer patients. ERRα overexpression in murine 4T1 breast cancer cells promoted spontaneous bone micro-metastases formation when tumor cells were inoculated orthotopically, whereas lung metastases occurred irrespective of ERRα expression level. In vivo, Rank was identified as a target for ERRα. That was confirmed in vitro in Rankl stimulated tumor cell invasion, in mTOR/pS6K phosphorylation, by transactivation assay, ChIP and bioinformatics analyses. Moreover, pharmacological inhibition of ERRα reduced primary tumor growth, bone micro-metastases formation and Rank expression in vitro and in vivo. Transcriptomic studies and meta-analysis confirmed a positive association between metastases and ERRα/RANK in breast cancer patients and also revealed a positive correlation between ERRα and BRCA1
carriers. Taken together, our results reveal a novel ERRα/RANK axis by which ERRα in primary breast cancer promotes early dissemination of cancer cells to bone. These findings suggest that ERRα may be a useful therapeutic target to prevent bone metastases.
Two lines of transgenic mice, hAIItg-δ and hAIItg-λ, expressing human apolipoprotein (apo)A-II at 2 and 4 times the normal
concentration, respectively, displayed on standard chow postprandial ...chylomicronemia, large quantities of very low density
lipoprotein (VLDL) and low density lipoprotein (LDL) but greatly reduced high density lipoprotein (HDL). Hypertriglyceridemia
may result from increased VLDL production, decreased VLDL catabolism, or both. Post-Triton VLDL production was comparable
in transgenic and control mice. Postheparin lipoprotein lipase (LPL) and hepatic lipase activities decreased at most by 30%
in transgenic mice, whereas adipose tissue and muscle LPL activities were unaffected, indicating normal LPL synthesis. However,
VLDL-triglyceride hydrolysis by exogenous LPL was considerably slower in transgenic compared with control mice, with the apparent
V
max of the reaction decreasing proportionately to human apoA-II expression. Human apoA-II was present in appreciable amounts
in the VLDL of transgenic mice, which also carried apoC-II. The addition of purified apoA-II in postheparin plasma from control
mice induced a dose-dependent decrease in LPL and hepatic lipase activities. In conclusion, overexpression of human apoA-II
in transgenic mice induced the proatherogenic lipoprotein profile of low plasma HDL and postprandial hypertriglyceridemia
because of decreased VLDL catabolism by LPL.
The roles of transforming growth factor-beta (TGFbeta) in heart or skeletal muscle development and physiology are still the subject of controversies. Our aim was to block, in transgenic mice, the ...TGFbeta signalling pathway by a dominant negative mutant of the TGFbeta type II receptor fused to the enhanced green fluorescent protein (TbetaRII-KR-EGFP) under the control of a 7.1 kbp mouse beta-myosin heavy chain (betaMHC) promoter to investigate the roles of TGFbeta in the heart and slow skeletal muscles. First, we generated two transgenic lines overexpressing EGFP under the control of the 7.1 kbp betaMHC promoter. In embryos, EGFP was detectable as early as 7.5 days post coitum. In embryos, newborns and adults, EGFP was expressed mainly in the cardiac ventricles and in slow skeletal muscles. EGFP expression was intense in the bladder but weak in the intestines. In contrast to the endogenous betaMHC promoter, the activity of the 7.1 kbp betaMHC promoter in the transgene was not repressed after birth and remained high in adult transgenic mice. We obtained two founders with the transgene comprising the TbetaRII-KR-EGFP sequence under the control of the 7.1 kbp betaMHC promoter. These founders were generated at a very low frequency and expressed barely detectable levels of TbetaRII-KR-EGFP mRNA. Our failure to obtain transgenic lines overexpressing the dominant negative receptor suggests that the blocking of the TGFbeta signalling pathway in the heart and slow skeletal muscles could be embryonically lethal. To conclude, the 7.1 kbp betaMHC promoter directs high levels of transgene expression in the cardiac ventricles and in slow skeletal muscles of the mouse. Analysis of the consequences of the blocking of the TGFbeta signalling pathway in the heart will require the use of tissue specific means of conditional gene invalidation.
Human apolipoprotein A‐II (apo A‐II) consists of three potential amphipathic helices of 17 residues each, which contribute to the lipid‐binding properties of this apolipoprotein. The conformation and ...lipid‐binding properties of these peptides, either as single‐helix or as two‐helix peptides, were investigated by turbidity, fluorescence, electron‐microscopy and circular‐dichroism measurements, and are compared in this article. The lipid affinity of shorter C‐terminal segments of apo A‐II was compared with those of the single‐helix or two‐helix peptides, to define the minimal peptide length required for stable complex formation. The properties of the apo‐A‐II‐(13–48)‐peptide were further compared with those of the same segment after deletion of the Ser31 and Pro32 residues, because the deleted apo‐A‐II‐(13–30)‐(33–48)‐peptide, is predicted to form a long uninterrupted helix.
The single helices of apo A‐II could not form stable complexes with phospholipids, and the helix‐turn‐helix segment spanning residues 13–48 was not active either. The apo‐A‐II‐(37–77)‐peptide and the apo‐A‐II‐(40–73)‐peptide could form complexes with lipids, which appear as discoidal particles by negative‐staining electron microscopy. The shortest C‐terminal domain of apo A‐II, able to associate with lipids to form stable complexes was the apo‐A‐II‐(40–73)‐peptide, which consisted of the C‐terminal helix, a β‐turn and part of the preceding helix. The shorter apo‐A‐II‐(49–77)‐peptide, and the helical apo‐A‐II‐(13–30)‐(33–48)‐peptide, could also associate with phospholipids. The complexes formed were, however, less stable, as they dissociated outside the transition temperature range of the phospholipid.
These data suggest that the C‐terminal pair of helices of apo A‐II, which is the most hydrophobic pair, is responsible for the lipid‐binding properties of the entire protein. The N‐terminal pair of helices of apo A‐II at residues 13–48 does not associate tightly with lipids. The degree of internal similarity and the cooperativity between the helical segments of apo A‐II is thus less pronounced than in apo A‐I or apo A‐IV. The N‐terminal and C‐terminal domains of apo A‐II appear to behave as two distinct entities with regard to lipid‐protein association.
The human corticotropin-releasing factor receptor type 1 (hCRF-R1) functional transcript is mainly expressed in the anterior pituitary corticotrophs, a tissue usually not available for clinical ...investigation. Splice variants translated into defective isoforms of the receptor have been described in few peripheral tissues. The aim of this work was to determine whether peripheral white blood cells from healthy individuals, an accessible tissue for clinical investigation, were suitable for the analysis of the hCRF-R1 transcript and gene. We report that: (i) specific amplification of the hCRF-R1 transcript from peripheral white blood cells mRNAs is feasible; (ii) this transcript is similar to the functional transcript; (iii) the draft sequence of chromosome 17 and unrelated sequences allow direct sequencing of all 14 exons of the gene, adjacent splice sites and related branch points. In conclusion, these approaches would be suitable for studies in patients having isolated secondary glucocorticoids deficiency to implicate the hCRH-R1 in the etiology of the disease.
Abstract
Funding Acknowledgements
Type of funding sources: None.
Introduction
Remote monitoring (RM) technologies have the potential to improve patient care by increasing compliance, providing early ...indications of heart failure (HF) decompensation, and potentially allowing for optimization of therapy to prevent HF admissions. The aim of this observational, retrospective study was to assess the clinical and economic consequences of RM vs standard monitoring (SM) through in-office cardiology visits, in patients carrying an implantable cardioverter defibrillator (ICD) or a cardiac resynchronization therapy defibrillator (CRTD).
Methods
Clinical and resource consumption data of this retrospective analysis were extracted from the Electrophysiology Registry of our Cardiology Unit, which has been systemically collecting patient information from January 2011 to February 2022. From a clinical standpoint, survival analysis was conducted, and incidence of CV-related hospitalizations was measured. From an economic standpoint, direct costs of RM and SM patients were collected to compare the cost per treated patient over a 2-year time horizon. Propensity score matching (PSM) was used to reduce the effect of confounding biases and the unbalance of patient characteristics at baseline.
Results
In the enrollment period, N=402 patients carrying ICD/CRTD met the inclusion criteria and were included in the analysis (N=189 patients -47.0%- followed through SM; N=213 patients -53.0%- followed through RM). After PSM, comparison was limited to N=191 patients in each arm (Figure 1). After a follow-up of 2 years since ICD/CRTD implantation, mortality rate for any cause was 1.6% in the RM group and 19.9% in the SM group (log-rank test, p<0.0001). Also, a lower proportion of patients in the RM group (25.1%) were hospitalized for CV-related reasons, compared to the SM group (51.3%; p<0.0001, two-sample test for proportions). Overall, the implementation of the RM program in our territory was cost-saving in both payer and hospital perspectives. The investment required to fund RM (a fee for service in the payer perspective, and staffing costs for hospitals), was more than offset by the lower rate of hospitalizations for CV-related disease. RM adoption generated savings of -€4,771 and -€6,752 per patient in 2 years, in the payer and hospital perspective, respectively (Figure 2).
Conclusion
RM of patients carrying ICD/CRTD improves short-term (2-year) morbidity and mortality risks, compared to SM (based on the traditional in-office visit approach) and finally reduces direct management costs for both hospitals and healthcare services
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